Ecostop Project: the “Start n Stop” railway

The "EcoStop" Start n Stop system designed by Colas Rail, a subsidiary of the Bouygues Group, stops the main diesel engine when the trains are parked or waiting, while maintaining comfort in the cab, thus making significant savings in terms of diesel fuel.

Main project's drivers for reducing the greenhouse gas (GHG) emissions

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Energy and resource efficiency

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Energy Decarbonisation

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Energy efficiency improvements

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Improving efficiency in non-energy resources

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Emission removal

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Financing low-carbon issuers or disinvestment from carbon assets

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Reduction of other greenhouse gases emission

Project objectives

Reducing fuel consumption on railway engines.
The objective of this project is to propose an efficient solution to reduce the running time of railway engines / locomotives when in slow-motion. Today, thanks to the telematics installed in all COLASRAIL DIESEL locomotives, it has been possible to establish precise statistics. The corollary of this data, based on a representative sample of railcars, shows an average daily idling rate of 56%.

Detailed project description

The Start n Stop on a railway engine is similar to the operation on a car, however research has led to significant improvements that have led Colas Rail to file a patent (publication in the Bulletin Officiel de la Publication Industrielle scheduled for September 2021).


The railway Start n Stop supervises:

  • Battery charge,
  • Engine temperature,
  • Engine air demand,
  • The braking of the machine,
  • The movement,
  • Safety equipment.

When these conditions are met, the engine stops.


The advantages of the system:

  • The system uses the sensors already in place on the machine, and these sensors are included in the maintenance cycle.
  • The start n stop is designed to manage the energy available within the machine, so it uses the auxiliary group or solar cells or other energies as a real load-shedding device. It is thanks to this concept that it can keep the air conditioning stopped for several hours and the batteries charged.
  • The EcoStop integrates a Multiple Unit management system specific to the railway.
  • When the engine is running, after a time calculated by the AI, the engine will automatically shut down. Research has allowed us to consider the psychological stress of the driver caused by the engine shutdown and has led us to imagine a system to eliminate this stress.


The gains provided by the system:

  • By stopping the main engine during the parking or waiting phases, it allows important gains on the fuel consumption associated with the reduction of atmospheric pollution, and also reduces the acoustic pollution.
  • The direct consequence is on the consumption, but there are also indirect consequences such as the reduction of the maintenance costs of the diesel engines, and on many other organs of the machines (transmission, boxes, etc…)

Emission scope(s)

on which the project has a significant impact

Scope 1

Direct emissions generated by the company's activity.

Scope 2

Indirect emissions associated with the company's electricity and heat consumption.

Scope 3

Emissions induced (upstream or downstream) by the company's activities, products and/or services in its value chain.

Emission Removal

Carbon sinks creation, (BECCS, CCU/S, …)

Avoided Emissions

Emissions avoided by the activities, products and/or services in charge of the project, or by the financing of emission reduction projects.

Scope 1 – Railway Start n Stop system

Pre-project situation :

  • Number of vehicles = 1
  • Average diesel consumption = 57949 Liters/year

  • Number of vehicules = 1
  • Average diesel consumption = 57949 Liters/year
  • Average distance travelled = 78300km/year
  • Diesel emission factor according to ADEME = 3170 gCO2eq/L

Initial emissions = 183 tCO2eq/year

After -project situation

  • Number of vehicles = 1
  • Average diesel consumption = 50995 Liters /year that is -12% by the reduction of the engine idle.
  • Average distance travelled = 78300km/year
  • Diesel emission factor according to ADEME = 3170 geco2eq/L

Final emissions = 161 tCO2eq/year

That is to say on the scope1 = – 22 tCO2eq/year/machine

The EN590 standard specifies that 1 liter of diesel weighs 835 grams. The ADEME specifies that the GNR carbon emission factor is 3.17kgco2/Liter.
We measure a 12% reduction in consumption thanks to the EcoStop system, i.e. 6954 liters/year based on the average total consumption of 57949 liters, we therefore calculate a reduction in the carbon footprint of 22044 kgco2/year.

Key points

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Invested amount


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Starting date of the project


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Project localisation


Project maturity level

Prototype laboratory test (TRL 7)

Real life testing (TRL 7-8)

Pre-commercial prototype (TRL 9)

Small-scale implementation

Medium to large scale implementation

Economic profitability of the project

Short term (0-3 years)

Middle term (4-10 years)

Long term (> 10 years)

Illustrations of the project

The Start n Stop project contributes to SDG 12 Responsible Consumption and Production. The EcoStop helps to change the behavior of railway users. It makes them realize that by using the EcoStop every day, they consume less fuel, and thus do something for the planet by consuming fewer fossil resources.

High reproducibility potential.

The technology is adaptable to all rail vehicle technologies.

Creation of the 100% Colas Rail project, patent filing in August 2020.

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Contact the company carrying the project :

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